The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 21, 1995
Filed:
Sep. 02, 1992
Shozo Miyagawa, Kyoto, JP;
Rohm Co., Ltd., Kyoto, JP;
Abstract
The present invention provides a modulation/ demodulation circuit and a communication system utilizing the modulation/demodulation circuit. The modulation/ demodulation circuit can be operated in either of a modulation/demodulation mode wherein an input signal is frequency inverted and scrambled or descrambled and a through mode wherein the input signal is directly outputted therefrom without being subject to any processing. In a private communication system, two such modulation/ demodulation circuits are used as a scrambler in the transmission-side and as a descrambler in the reception-side. In order to prevent the low band characteristic of the reception-side output in the through mode from being different from that of the modulation/demodulation mode, the modulation/demodulation circuit may include a high pass filter. The high pass filter a low band cut-off characteristic reciprocal to a low pass filter for removing the upper side band from the output of a double balanced mixer.